Autoflower - 400w MH 18/6 or 600w HPS 12/12?

I'm reading a lot about how moving autoflowers to 12/12 after sexing actually reduces yield.

My MH is only 400w and is set on 18/6. My HPS on 12/12 is 600w. I've been keeping it under the MH until they show hairs, then moving them to the HPS on 12/12.

Would it be better for me to keep them under the 18/6 MH, and if so, would the lack of red lighting reduce yield? Could I keep it under the MH and just add some extra CFLs that give off the orange/red color? (I forget the K rating) and.....if I do that, will the red lighting affect the other plants under the 18/6 that aren't quite in flower?

Which would be better?

Who knew you'd have to think so damned hard to do this....

I wondered the same thing, and did some reading. The auto-flower plants do not recognize the light change and so therefore the more energy they receive, the better.

18/6 20/4 is what i have used/ good luck if this helps!

the different types of lights and different wattages make this a very tricky question to answer. if you cant run the 600w hps for longer than 12/12, your best bet would be to put a few plants under the 600 12/12 and a few under the 400 18/6... and see which ones come out better... your question is specific to your situation, so i doubt many people, if any, will have actually tried both situations youre asking about. theyll just be guessing for the most part. honestly, if you dont try both for yourself and just listen to what people on here say, there will be about a 50% chance youre wrong lol

it wont hurt anything at all to add a few 2700k cfls to your mh light though, i almost always veg under hps anyway, even though i have a mh as well.

oh and my money is on the 600 at 12/12 giving better results than the 400 at 18/6 just because of the increased power and more appropriate flowering spectrum. could be wrong though.

Thanks for the responses. I'm going to split them and watch the results. I have 3 Diesel Ryders that just showed their girlyhood. I'll keep you posted.

In the event it turns out it likes the 400w-er better, would there be any adverse reactions if I took some that were already in flower under the 12/12 600 HPS, and put them back to 18/6?

Well, I think I have an answer to this question. I had 3 diesel ryders and 3 smurfberry autos.

I measure my plants about every two days and chart growth. I put two of one plant and one of the other under 12/12 HPS and left the remaining in 18/6 MH. All the ones under 18/6 capped out at 15-ish inches and stopped growing. Buds grew, but they were kinda pitiful. Meanwhile, the plants in 12/12 kept growing and the buds were thicker. About 3 weeks into flowering I moved the 3 in 18/6 to 12/12 and within days they started growing again.

That answered it for me. Although autoflowers will grow in 18/6 under MH after sexed, they do better in 12/12 under HPS.

auto flower....love it.. what I have done Is i do as much light untill the show signs of flower and then bring light to 12/12.

I will do up to 24hours on untill they show signs of flowering. !!!

good luck

I like the autoflowers because they're quick, but so far, I'm disappointed with yield. I keep trying different types, but so far, I'm only pulling an oz or so off each plant.